Breastpumps are well known, and generally comprise a hood or shield that fits over the breast, and a vacuum pump connected to the shield for generating an intermittent vacuum (negative pressure) within the shield. In its simplest and most common form, an intermittent suction action of the vacuum pump serves to pull on the breast and massage it so as to extract milk. The extracted milk typically drains from the shield into a collection container, such as a baby bottle, which is ordinarily attached directly to the breastshield apparatus.
Inserts for use within the hood or shield of a rigid breastshield assembly are also known, and have been used for sizing the breastshield. That is, an insert would be used in a larger funnel-shaped breastshield to reduce the internal diameter of the cone portion and/or nipple tunnel, for a smaller breast. Some rigid-type breastshields have also sometimes been employed with a flexible breast-engaging portion or device mounted interior of a rigid external support or frame, not so much as a sizing mechanism but in an attempt at improved milk expression as well as comfort. In the latter application, an intermittent suction (negative pressure) is applied in the space between the flexible membrane and outboard support, causing the membrane to cyclically collapse and then return to its rest state, thereby gently massaging the breast and/or the nipple, for milk expression.
In most instances, the pressure applied at the breast is a negative pressure (suction), as noted above. That negative pressure is typically applied to the interior of the breastshield in a singular fashion, that is, without any kind of differential pressure application over the breastshield as a whole. This has ordinarily been done through a cyclic pattern (e.g., intermittent) of suction only. There have also been some efforts to provide a breastshield which has a positive pressure applied at the breast, that is, a compressive force around a portion that is capable of expanding (inflating).
The present invention has its genesis in an improved breastshield, breastpump assembly and method for operating the same, which seeks to combine various attributes of positive and/or negative pressure applications, as well as differential sequencing of how one or both are applied in operation.